•Elastic modulus and TS can be estimatedalong fiber direction By Rule of Mixtures

•Properties can be isotropic or anisotropic

Structural:

•Based on build-up of sandwiches inlayered form

–Plys

–HoneyCombs

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Bruce Mayer, PE

Engineering-45: Materials of Engineering

WhiteBoard Work

Prob 16.11

•Given IsoStrain,Longitudinal Loadingfor a ContinuousFiber Composite:

fmcFFF+=•Then Show

mmffmfVEVEFF=•Where

–F

Force

–E

Elastic Modulus

–V

Volume fraction

–Sub-f → “fiber”

–Sub-m → “matrix”

–Sub-c → “composite”

BMayer@ChabotCollege.edu • ENGR-45_Lec-28_Composites.ppt

31

Bruce Mayer, PE

Engineering-45: Materials of Engineering

Bruce Mayer, PE

Licensed Electrical & Mechanical Engineer

BMayer@ChabotCollege.edu

Chabot Engineering

Appendix

E-glass

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Bruce Mayer, PE

Engineering-45: Materials of Engineering

E Glass-

BackGround

http://www.azom.com/details.asp?ArticleID=764

Background

•E-Glass or electrical grade glass wasoriginally developed for stand off insulatorsfor electrical wiring. It was later found tohave excellent fibre forming capabilitiesand is now used almost exclusively as thereinforcing phase in the material commonlyknown as fibreglass.

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Bruce Mayer, PE

Engineering-45: Materials of Engineering

E Glass-

Composition

Composition

•E-Glass is a low alkali glass with a typicalnominal composition of SiO2

54wt%, Al2O3

14wt%, CaO+MgO 22wt%, B2O3

10wt%and Na2O+K2O less then 2wt%. Someother materials may also be present atimpurity levels.

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Bruce Mayer, PE

Engineering-45: Materials of Engineering

E Glass–

Key Properties

Properties that have made E-glass so popular infibreglass and other glass fibre reinforced compositeinclude:

•Low cost

•High production rates

•High strength, (see table on next slide)

•High stiffness

•Relatively low density

•Non-flammable

•Resistant to heat

•Good chemical resistance

•Relatively insensitive to moisture

•Able to maintain strength properties over a wide range ofconditions

•Good electrical insulation

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Bruce Mayer, PE

Engineering-45: Materials of Engineering

E Glass–

Fibre Strength

Table 1.Comparison of typicalproperties for some common fibres.

Materials

Density (g/cm3)

Tensile Strength(MPa)

Young modulus(GPa)

E-Glass

2.55

2000

80

S-Glass

2.49

4750

89

Alumina (Saffil)

3.28

1950

297

Carbon

2.00

2900

525

Kevlar 29

1.44

2860

64

Kevlar 49

1.44

3750

136

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Bruce Mayer, PE

Engineering-45: Materials of Engineering

E Glass–

Use in Composites

The use of E-Glass as the reinforcement material inpolymer matrix composites is extremely common.Optimal strength properties are gained when straight,continuous fibres are aligned parallel in a singledirection. To promote strength in other directions,laminate structures can be constructed, withcontinuous fibres aligned in other directions. Suchstructures are used in storage tanks and the like.

Random direction matts and woven fabrics are alsocommonly used for the production of compositepanels, surfboards and other similar devices.